Add Support for deeper update using $set

[romayalon]

Signed-off-by: Romy romy2232@gmail.com

This PR handles an issue I observed when executing updates using $set op with more than 1 '.' .

For example:

When calling:
convertUpdate('data', { $set: { 'a.b.c': 2 } }

Actual Postgres query:
jsonb_set(jsonb_set(jsonb_set(data,'{a}',COALESCE(data->'a', '{}'::jsonb)),'{b}',COALESCE(data->'a'->'b', '{}'::jsonb)),'{a,b,c}','2'::jsonb)

This query indeed updates a.b.c as wanted but it also "hangs" the old value of a.b on a.

Expected Postgres query:
jsonb_set(jsonb_set(jsonb_set(data,'{a}',COALESCE(data->'a', '{}'::jsonb)),'{a,b}',COALESCE(data->'a'->'b', '{}'::jsonb)),'{a,b,c}','2'::jsonb)

Please review,
Thank you.

[thomas4019]

Fix looks good and thanks for adding a test.